Starter Motor Noise Diagnosis; No-Load Test Connections; High Frequency - Jeep J-10 Series 1982 Technical & Service Manual

1F-4 STARTING SYSTEMS
Starter Motor Noise Diagnosis
CONDITION
POSSIBLE CAUSE
CORRECTION
HIGH FREQUENCY
WHINE BEFORE
ENGINE STARTS;
ENGINE STARTS OK.
(1)
Excessive distance between pinion
gear and flywheel/drive plate gear.
(1) Shim starter motor toward flywheel
/drive plate.
HIGH FREQUENCY
WHINE AFTER
ENGINE STARTS
WITH IGNITION
KEY RELEASED.
ENGINE STARTS OK.
(1)
Insufficient distance between
starter motor pinion gear and
flywheel/drive plate gear. Fly
wheel/drive plate runout can
cause noise to be intermittent.
(1)
Shim starter motor away from
flywheel/drive plate. Inspect
flywheel/drive plate for damage;
bent, unusual wear, and excessive
runout. Replace flywheel/drive
plate as necessary.
A LOUD "WHOOP"
AFTER ENGINE
STARTS WHILE
STARTER MOTOR IS
ENGAGED.
(1)
Most probable cause is defective
overrunning clutch. Clutch
replacement normally corrects
this condition.
(1)
Replace overrunning clutch or drive
assembly.
A "RUMBLE",
"GROWL" OR
"KNOCK" AS
STARTER MOTOR
COASTS TO STOP
AFTER ENGINE
STARTS.
(1)
Most probable cause is bent or
unbalanced starter motor
armature. Armature replacement
normally corrects this condition.
(1)
Replace starter motor armature.
(2) Low no-load speed and high current flow
indicate:
(a) Too much friction-—tight, dirty, or worn
bearings, bent armature shaft or bent frame causing
armature to drag.
(b) Shorted armature winding. This can be fur
ther determined on growler after disassembly.
(c) Grounded armature or field windings. In
spect further after disassembly.
(3) No armature rotation and high current flow
indicate:
(a) Terminal or field windings shorted to
ground.
(b) Seized bearings (this should have been de
termined by turning armature by hand).
(4) No armature rotation and no current flow
indicate:
(a) Open field winding circuit. This can be de
termined after disassembly by inspecting internal con
nections and testing circuit with test lamp.
(b) Open armature windings. Inspect commuta
tor for badly burned bars after disassembly.
(c) Broken brush springs, worn brushes, pro
truding insulation between commutator bars or other
causes that would prevent good contact between brushes
and commutator.
90559
Hg. 1F-4 No-Load Test Connections
(5) Low no-load speed and low current flow indicate
high internal resistance because of poor connections,
defective wires, dirty commutator and causes listed un
der step (4) above.
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